There is known a backhoe including an implement to which a variety of attachments such as a breaker, a grapple, etc. can be selectively attached (see e.g. Japanese Patent Application “Kokai” No. 2002-39373). The attachment can be moved in association with an operation of an actuator such as a hydraulic cylinder by means of an operational member provided at an operator's section. The operational member can be operated when the engine of the backhoe is being driven. Hence, if the operational member is operated under such condition, the actuator is activated to move the attachment.